Socket liner for artificial limb

ABSTRACT

A hypobarically-controlled artificial limb for amputees includes a single socket with a volume and shape to receive a substantial portion of the residual limb. A sealed cavity is formed between the socket and the residual limb. The wearer may use a liner over the residual limb for comfort. A vacuum source is connected to a vacuum valve connected to the cavity to suspend the artificial limb from the residual limb and to control and minimize volumetric and fluid changes within the residual limb. A liner for a hypobarically-controlled socket for an artificial limb, with a liner interface bonding the liner to the socket and forming a seal between the liner and the socket. The liner may be permanently attached to the socket or the liner may be removed from the socket for replacement.

[0001] This is a continuation of U.S. patent application Ser. No.09/670,853, filed on Sep. 27, 2000, which is a continuation-in-part ofU.S. patent application Ser. No. 09/492,406, filed Jan. 27, 2000, whichis a continuation-in-part of U.S. patent application Ser. No.09/325,297, filed Jun. 3, 1999.

BACKGROUND OF THE INVENTION

[0002] The present invention relates to prosthetic devices and moreparticularly to a hypobarically-controlled artificial limb for amputees.

[0003] An amputee is a person who has lost part of an extremity or limbsuch as a leg or arm that commonly may be termed as a residual limb.Residual limbs come in various sizes and shapes with respect to thestump. That is, most new amputations are either slightly bulbous orcylindrical in shape while older amputations that may have had a lot ofatrophy are generally more conical in shape. Residual limbs may furtherbe characterized by their various individual problems or configurationsincluding the volume and shape of a stump and possible scar, skin graft,bony prominence, uneven limb volume, neuroma, pain, edema or soft tissueconfigurations.

[0004] Referring to FIGS. 1 and 2, a below the knee residual limb 10 isshown and described as a leg 12 having been severed below the kneeterminating in a stump 14. In this case, the residual limb 10 includessoft tissue as well as the femur 16, knee joint 18, and severed tibia 20and fibula 22. Along these bone structures surrounded by soft tissue arenerve bundles and vascular routes that must be protected againstexternal pressure to avoid neuromas, numbness and discomfort as well asother kinds of problems. A below the knee residual limb 10 has its stump14 generally characterized as being a more bony structure while an abovethe knee residual limb may be characterized as including more softtissue as well as the vascular routes and nerve bundles.

[0005] Referring to FIG. 2, amputees who have lost a part of their arm26, which terminates in a stump 28 also may be characterized as havingvascular routes, nerve bundles as well as soft and bony tissues. Theresidual limb 10 includes the humerus bone 30 that extends from belowthe shoulder to the elbow from which the radius 34 and ulna 36 bones maypivotally extend to the point of severance. Along the humerus bone 30are the biceps muscle 38 and the triceps muscle 40 which still yet maybe connected to the radius 34 and the ulna, 36, respectively.

[0006] In some respects, the residual limb amputee that has a severedarm 26 does not have the pressure bearing considerations for anartificial limb but rather is concerned with having an artificial limbthat is articulable to offer functions typical of a full arm, such asbending at the elbow and grasping capabilities. An individual who has aparalyzed limb would also have similar considerations wherein he or shewould desire the paralyzed limb to having some degree of mobility andthus functionality.

[0007] Historically, artificial limbs typically used by a leg amputeewere for the most part all made out of wood such as an Upland Willow.The limbs were hand carved with sockets for receiving the stump 14 ofthe residual limb 10. Below the socket would be the shin portion withthe foot below the shin. These wooden artificial limbs were covered withrawhide, which often were painted. The sockets of most wood limbs werehollow as the limbs were typically supported in the artificial limb bythe circumferential tissue adjacent the stump 14 rather than at thedistal end of the stump 14.

[0008] Some artificial limbs in Europe were also made from forged piecesof metal that were hollow. Fiber artificial limbs were also used whichwere stretched around a mold after which they were permitted to dry andcure. Again, these artificial limbs were hollow and pretty muchsupported the residual limb about the circumferential tissue adjacentthe stump 14.

[0009] All of these various artificial limbs have sockets to put theamputee's stump 14 thereinto. There are generally two categories ofsockets. There are hard sockets wherein the stump goes right into thesocket actually touching the socket wall without any type of liner orstump sock. Another category of sockets is a socket that utilizes aliner or insert. Both categories of sockets typically were opened endedsockets where they had a hollow chamber in the bottom and no portion ofthe socket touched the distal end of the stump 14. So, the stump wassupported about its circumferential sides as it fits against the insidewall of the sockets.

[0010] These types of sockets caused a lot of shear force on the stump14 as well as had pressure or restriction problems on the nerve bundlesand vascular flow of fluid by way of the circumferential pressure effectof the socket on the limb. This pressure effect could cause a swellinginto the ends of the socket where an amputee may develop severe edemaand draining nodules at the end of their stump 14.

[0011] With time, prosthetists learned that by filling in the socket'shollow chamber and encouraging a more total contact with the stump andthe socket, the swelling and edema problems could be eliminated.However, the problematic tissue configurations, such as bonyprominences, required special consideration such as the addition of softor pliable materials to be put into the socket.

[0012] Today, most artificial limbs are constructed from thermosetplastics such as polyester resins, acrylic resins, polypropylenes andpolyethylenes, which are perhaps laminated over a nylon stockinette thatalso may be impregnated by the various resins.

[0013] In the past, most artificial limbs were suspended from theamputee's body by some form of pulley, belt or strap suspension oftenused with various harnesses and perhaps leather lacers or lacings.Another method of suspending artificial limbs is known as the wedgesuspension wherein an actual wedge is built into the socket that is moreclosed at its top opening. The wedge in the socket cups the medialfemoral condyle or knuckle at the abductor tubical. Yet another form ofsuspension is referred to as the shuttle system or a mechanical hookupor linkup wherein a thin suction liner is donned over the stump that hasa docking device on the distal end which mechanically links up with itscooperative part in the bottom of the socket chamber. Sleeve suspensionswere also used wherein the amputee may use a latex rubber tube whichforms into a rubber-like sleeve which would be rolled on over both thetop of the artificial limb and onto the amputee's thigh. The sleevesuspensions have been used in combination with other forms ofsuspensions techniques.

[0014] Both the use of a positive pressure system and the use of anegative pressure system (or hypobaric closed chamber) have beenutilized in the field of prosthetics. At one time, for pressure systems“inflatable inner tubes” were used to fit into sockets. Presently, thereare pneumatic “bags” which are strategically placed over what peopleconsider to be good weight-bearing areas to increase pressure to helpaccommodate for volume changes within the socket.

[0015] The problem with this is that it is a very specific pressure andcreates atrophy and loss of tissue dramatically over these high pressureareas. None of these systems employs positive pressure distributed overthe total contact area between the residual limb and the artificial limbsocket to accommodate volume changes within the socket.

[0016] The negative pressure aspects have been utilized for a closedchamber in that a socket is donned by pulling in with a sock, pullingthe sock out of the socket and then closing the opening with a valve.This creates a seal at the bottom and the stump is held into the socketby the hypobaric seal. However, there are no systems that employ anegative pressure produced by a vacuum pump to lock the residual limb tothe artificial limb.

[0017] The older systems were initially started in Germany. They were anopen-ended socket, meaning there was an air chamber in the bottom of thesocket. This did not work particularly well because it would causeswelling of the residual limb into the chamber created by the negativedraw of suspending the weight of the leg and being under a confinedarea. This would lead to significance edema that would be severe enoughto cause stump breakdown and drainage.

[0018] It was later discovered in America that total contact wasessential between the residual limb and the socket and once you hadtotal contact the weight was distributed evenly or the suspension wasdistributed over the whole surface of the limb rather than just over theopen chamber portion of the socket.

[0019] The human body as a whole is under approximately one atmosphereof pressure at sea level. It keeps and maintains a normal fluid systemthroughout the body. When an amputee dons a prosthesis and begins takingthe pressures of transmitting the weight of the body through the surfacearea of the residual limb to the bone, there is increased pressure onthe residual limb equal to one atmosphere plus whatever additionalpressures are created by weight bearing. This increased pressure causesthe eventual loss of fluids within the residual limb to the largerportion of the body that is under less pressure. This loss of fluidscauses the volume of the residual limb to decrease during the day. Itvaries from amputee to amputee, but it is a constant among all amputeeand the more “fleshy” and the softer the residual limb, the more volumefluctuation there will be. The greater the weight and the smaller thesurface area, the greater the pressures will be and the more “swings”there will be in fluids. In the past, the amputee had to compensate forthis volume decrease by removing the artificial limb and donningadditional stump socks to make up for the decreased residual limbvolume.

[0020] While some of these devices addressed some of the problemsassociated with prosthetics, none of the artificial limbs, liners andsocket, individually or in combination, offered a prosthesis thatpresented a total contact relationship with the residual limb; absorbedand dissipated shear, shock and mechanical forces transmitted to thelimb tissues by the artificial limb; controlled residual limb volume;and used negative pressure as a locking device to hold the residual limbinto the socket.

[0021] There is a need for an improved hypobarically-controlledartificial limb that will offer total contact relationship with theresidual limb; absorb and dissipate shock, mechanical and shear forcestypically associated with ambulation, twisting and turning and weightbearing with an artificial limb; control residual limb volume by way ofeven weight distribution; use negative pressure as a locking device tohold the residual limb into the socket; and to totally adjust and adaptthe internal socket environment to changes in residual limb volume; andcontrol stump volume changes by a negative pressure system which is alsocapable of providing positive pressure. Ideally, the vacuum systemshould be automatically regulated.

[0022] There is also a need for an improved hypobarically-controlledartificial limb with a positive mechanical interlock between an innersocket, which receives the residual limb, and an outer socket thatattaches to the shin and foot of the artificial limb. Both the innersocket and the outer socket should have a rigid lower portion forweight-bearing and a substantially flexible upper portion to allowmovement of the residual limb.

[0023] In the past, artificial limbs had to be custom-built for theamputee. The custom building process generally consisted of: placing asingly ply thin cotton casting sock over the residual limb; making afirst negative mold of the residual limb for forming an orthopedicplaster wrap about the residual limb and casting sock; making a firstpositive model of the residual limb by filling the negative mold withplaster; forming a thermoplastic foam about the positive model to createa space for a liner; adding additional thermoplastic foam to form adistal end cap as well as other areas which may require additionalthicknesses due to tissue configurations; forming a second enlargednegative plaster mold about the foam; removing the foam; pouring aliquid and moldable liner into the space between the positive model andthe second negative mold; allowing the liner to harden; removing theliner from the second negative mold; having the amputee don the linerover the residual limb; placing another single ply thin casting sockover the liner; making a third plaster wrap or negative mold of theartificial limb socket about the residual limb and the liner; removingthe liner from the third plaster wrap; making a plaster cast or positivemodel of the socket from dental plaster; milling or shaving the positivemodel to create a reduced positive model to create weight bearing areasand compression of the liner against the residual limb and the socket;and making the socket from the reduced positive model.

[0024] This custom-building process is expensive, time-consuming, andrequires the constant attention of a skilled prosthetist.

[0025] There is a need for a generic artificial limb socket that can befitted to the contours of the residual limb without the need for alengthy, expensive custom-molding process. The socket should contain asemi-compressible molding material which can be molded to the contoursof the residual limb under vacuum and/or positive air pressure.

SUMMARY OF THE INVENTION

[0026] A liner for a socket of an artificial limb, the socket configuredto receive a portion of an amputee's residual limb and the liner, theliner including a liner interface for bonding the liner and the socket.In one embodiment, the liner interface is configured to substantiallyseal the liner to the socket to minimize air leakage into space betweenthe liner and the socket.

BRIEF DESCRIPTION OF THE DRAWINGS

[0027]FIG. 1 is a side elevational view of the tissue and skeletalstructure of an amputee's residual limb;

[0028]FIG. 2 is a side elevational view of a residual limb in the formof an amputated arm showing the skeletal and muscular structure of theresidual limb;

[0029]FIG. 3 is an exploded elevational view of the residual limbdonning the polyurethane sleeve, stretchable nylon sleeve, liner, nylonsheath and socket of an artificial limb;

[0030]FIG. 4 is a cross-section of the artificial limb in FIG. 3, whichis a first embodiment of the artificial limb;

[0031]FIG. 5 is a cross-section of the artificial limb similar to FIG.4, showing a second embodiment of the artificial limb;

[0032]FIG. 6 is the same as FIG. 5, but showing compression of the innersocket under the influence of positive air pressure;

[0033]FIG. 7 is a cross-section of the artificial limb showing a thirdembodiment of the artificial limb;

[0034]FIG. 8 is a cross-section of the artificial limb showing a fourthembodiment of the artificial limb;

[0035]FIG. 9 is an elevational view of the polyurethane sleeve andsecond stretchable nylon sleeve rolled over the socket and residual limbwith clothing shown in broken outline;

[0036]FIG. 10 is a cross-section of the artificial limb showing a fifthembodiment of the artificial limb;

[0037]FIG. 11 is a cross-section of the artificial limb showing a sixthembodiment of the artificial limb;

[0038]FIG. 12 is a detailed view of the vacuum mechanism in FIG. 11;

[0039]FIG. 13 is a cross-section of the artificial limb showing aseventh embodiment of the artificial limb;

[0040]FIG. 14 is a detailed view of the vacuum mechanism and suspensionsleeve of FIG. 13;

[0041]FIG. 15 is a cross-section of the artificial limb showing aneighth embodiment of the artificial limb;

[0042]FIG. 16 is a cross-section of the artificial limb showing a ninthembodiment of the artificial limb;

[0043]FIG. 17 is a cross section of the artificial limb showing a linerwith an annular seal;

[0044]FIG. 18 is a cross-section of the artificial limb showing a secondembodiment of the liner of FIG. 17;

[0045]FIG. 19 is a partial cross-section of the artificial limb showinga third embodiment of the liner of FIG. 17;

[0046]FIG. 20 is a partial cross-section of the artificial limb showinga fourth embodiment of the liner of FIG. 17; and

[0047]FIG. 21 is a partial cross-section of the artificial limb showinga liner with an adhering interface attaching the liner to the inside ofthe socket.

[0048]FIG. 22 is a detailed cross-section of the socket and liner withan adhering interface comprising hook-and-loop material.

[0049]FIG. 23 is similar to FIG. 22, but shows magnets rather thanhook-and-loop material.

DESCRIPTION OF THE PREFERRED EMBODIMENT

[0050]FIG. 3 shows the hypobarically-controlled artificial limb 50 ofthe present invention. The hypobarically-controlled artificial limb 50includes an outer socket 52, shin 54, and foot 56. The outer socket 52has a volume and shape to receive a substantial portion of the residuallimb 14 with a space 58 therebetween.

[0051] A first embodiment of the hypobarically-controlled artificiallimb 50 is shown in FIG. 4. The hypobarically-controlled artificial limb50 further includes a flexible inner socket 60 with a cavity 62 with avolume and shape for receiving a substantial portion of the residuallimb 14 and fitting in the space 58 between the outer socket 52 and theresidual limb 14. The inner socket 60 has an inner surface 64 opposingthe residual limb 14 and an outer surface 66 opposing the outer socket52.

[0052] A vacuum source 70 may conveniently be attached to the shin orpylon 54. The vacuum source 70 may preferably be a mechanical ormotor-driven pump 72. The vacuum source 70 is connected to a powersource 83, which may be a battery.

[0053] A vacuum valve 74 is suitably connected to the vacuum source 70.The vacuum valve 74 may preferably be disposed on the outer socket 52. Avacuum tube 76 connects the vacuum valve 74 to the cavity 62. It will beseen that the vacuum source will cause the residual limb 14 to be drawninto firm contact with the inner surface 64 of the inner socket 60.

[0054] The hypobarically-controlled artificial limb 50 also includes aregulator means 80 for controlling the vacuum source 70. Preferably, theregulator means 80 may be a digital computer 82. Alternately, theregulator means may be a vacuum regulator. The regulator means 80 isconnected to a power source 83, which may be a battery.

[0055] A seal means 84 makes an airtight seal between the residual limb14 and the outer socket 52. Preferably, the seal means 84 is anonfoamed, nonporous polyurethane suspension sleeve 86 which rolls overand covers the outer socket 52 and a portion of the residual limb 14.Alternatively, the seal means 84 may be any type of seal which isairtight.

[0056] The hypobarically-controlled artificial limb 50 may also includea thin sheath 90 between the residual limb 14 and the inner surface 64of the inner socket 60. As vacuum is applied to the cavity 62, thesheath 90 will allow the vacuum to be evenly applied throughout thecavity 62. Without the sheath 90, the residual limb 14 might “tack up”against the inner surface 64 and form a seal which might prevent evenapplication of the vacuum to the cavity 62. The sheath 90 may also beused to assist the amputee into a smooth and easy fitting into the innersocket 60. The sheath 90 is preferably made of thin knitted nylon.

[0057] The hypobarically-controlled artificial limb 50 may also includea nonfoamed, nonporous polyurethane liner 92 receiving the residual limb14 and disposed between the sheath 90 and the residual limb 14. Theliner 92 provides a total-contact hypobaric suction, equal weightdistribution socket liner. The liner 92 readily tacks up to the skin ofthe residual limb 14 and provides total contact with the limb 14. Theliner 92 absorbs and dissipates shock, mechanical and shear forcestypically associated with ambulation.

[0058] The hypobarically-controlled artificial limb 50 may also includea stretchable nylon second sleeve 94 for rolling over and covering thesuspension sleeve 86 to prevent clothing from sticking to and catchingthe suspension sleeve 86.

[0059] Referring to FIG. 3, the polyurethane tubular sleeve 86 may beappreciated alone and in combination with the urethane liner 92 togetherwith the optional nylon sheath 90 and second stretchable nylon sleeve94.

[0060] More specifically, the amputee takes the stretchable nylon secondsleeve 94, suitably made of a spandex-like material and rolls it up overthe stump 14 to the upper portions of the residual limb suitably as thethigh of a leg 12. Next, the polyurethane sleeve 86 is also rolledupwardly over the residual limb 10. Thereafter, the liner 92 isoptionally donned.

[0061] Next, the amputee may optionally utilize the nylon sheath 90which is suitably of a non-stretching, thin, friction reducing nylon. Asstated, this sheath 90 optionally may be used to assist the amputee intoa smooth and easy fitting into the inner socket 60. Alternatively, thesheath 90 may be avoided and the liner 92 simply inserted into the innersocket 60 of the artificial limb 50.

[0062] Next, the amputee simply grasps the rolled over portion of thepolyurethane sleeve 86 and rolls it over a substantial portion of theouter socket 52. The sleeve 86 makes an airtight seal between theresidual limb 14 and the outer socket 52.

[0063] As can be appreciated, the polyurethane sleeve 86 is tacky.Consequently, the stretchable nylon second sleeve 94 may be utilized androlled over the polyurethane sleeve 86.

[0064] The amputee then sets the regulator means 80 to cause the vacuumsource 70 to apply vacuum through the vacuum valve 74 and vacuum tube 76to the cavity 62. Enough vacuum is applied to cause the residual limb(with optional coverings) to be drawn firmly against the inner surface64 of the inner socket 60, which is flexible. The vacuum source 70 maypreferably maintain a vacuum in the range of 0 to 25 inches of mercury(ideally fifteen to twenty inches).

[0065] It will be seen that the vacuum within the inner socket 60 willcause the hypobarically-controlled artificial limb 50 to be suspendedfrom the residual limb 14. The vacuum will lock the residual limb 14into the inner socket 60 without causing swelling of the residual limbinto the socket, because of the total contact of the residual limb 14with the inner socket 60. That is, there is no open chamber between theresidual limb 14 and the inner socket 60 which would draw on theresidual limb.

[0066] As the volume of the residual limb 14 decreases during the daydue to weight-bearing pressures, the regulator means 70 mayappropriately adjust the vacuum source 70 to draw the residual limb 14more firmly against the inner socket 60 and thus compensate for the lossof residual limb volume. The vacuum may also partially oppose the lossof fluids from the residual limb caused by weight-bearing pressures.

[0067] A second embodiment of the hypobarically-controlled artificiallimb 50 is shown in FIGS. 5 and 6. The second embodiment of thehypobarically-controlled artificial limb 50 is as described above, withthe exception that the inner socket 60A is compressible as well as beingflexible. Instead of a vacuum source, the second embodiment has apositive air pressure source 100, which may preferably be a motor-drivenpump 102. The regulator means 80, which may be a digital computer 82,controls the positive air pressure source 100. The regulator means andpositive air pressure source 100 are connected to a power source (notshown), which may be a battery. A positive pressure valve 104 connectsthe space 58 to the positive air pressure source 100, for compressingthe inner socket 60A as the volume of the residual limb decreases.

[0068] It will be seen that as the volume of the residual limb 14decreases during the day due to weight-bearing pressures, the regulatormeans 80 may control the positive air pressure source 100 to cause airpressure to compress the inner socket 60A to compensate for thedecreased volume of the residual limb, as shown in FIG. 6.

[0069] A third embodiment of the hypobarically-controlled artificiallimb 50 is shown in FIG. 7. The third embodiment is a combination of thefirst and second embodiments described above.

[0070] The mechanical motor-driven pump 72 may act as both the vacuumsource 70 and the positive air pressure source 100. The regulator means80, vacuum source 70 and positive air pressure source 100 are connectedto a power source (not shown), which may be a battery.

[0071] The vacuum source 70, under control of the regulator means 80,will compensate for reduced residual limb volume up to a certain point.From that point on, the regulator means 80 will cause the positive airpressure source 100 to further compensate for reduced residual limbvolume as described above. The third embodiment thus uses both vacuumand positive air pressure working together to lock the residual limb 14into the inner socket 60 and reduce socket volume to compensate forfluid loss in the residual limb 14. The exact point at which thechangeover is made between vacuum compensation and positive air pressurecompensation is controlled by the regulator means 80, which as describedmay be a digital computer appropriately programmed for the socketenvironment.

[0072] A fourth embodiment of the hypobarically-controlled artificiallimb 50 is shown in FIG. 8. The fourth embodiment is like the firstembodiment, but includes two vacuum valves: a first vacuum valve 106 anda second vacuum valve 110, both connected to the vacuum source 70. Thefirst vacuum valve 106 connects the vacuum source 70 to the space 58.The space 58 contains a semi-compressible material 108, such aspolystyrene beads, as disclosed in U.S. Pat. No. 4,828,325, hereinincorporated by reference.

[0073] To don the artificial limb 50, the amputee proceeds as describedabove. After inserting the residual limb 14 (with optional coverings)into the inner socket 60B, which is both compressible and expandable,and rolling the suspension sleeve 86 over the outer socket 52, theamputee activates the regulator means 80, causing the vacuum source 70to apply a vacuum to the space 58. This causes the material 108 to lockmechanically together into a rigid mass, conforming to the shape of theresidual limb 14. The inner socket 60B may expand slightly under theweight of the residual limb 14 and under the influence of vacuum.

[0074] It will be seen that the semi-compressible molding material 108can be molded to the contours of the residual limb 14 without using acustom-building process to produce a custom socket. The outer socket 52may appropriately occur in standard sizes, such as small, medium, andlarge. The inner socket 60B may also occur in standard sizes such assmall, medium, and large. Adaptation of the inner socket 60B to thecontours of the residual limb 14 occurs through solidifying the material108 under the influence of vacuum.

[0075] The second vacuum valve 110 connects the vacuum source 70 to thecavity 62 as previously described, for locking the residual limb 14 intothe inner socket 60B.

[0076] The fourth embodiment may also include a positive air pressuresource 100 as previously described, to adjust the size of the innersocket 60B to compensate for decreased residual limb volume.

[0077] The fourth embodiment may also include a thin sheath 90, liner92, and second sleeve 94, as previously described (see FIG. 3).

[0078] The positive air pressure source 100 may also be used for shockabsorption and a dynamic response in the ankle and foot sections of theartificial limb 50, by means of a connection 120.

[0079] A fifth embodiment of the hypobarically-controlled artificiallimb 50 is shown in FIG. 10. This embodiment is the same as the firstembodiment shown in FIG. 4, with some changes. First, vacuum source 71may be a hand-operated vacuum pump 71 which may remove air from thecavity 62 down to approximately 15-25 inches of mercury. A suitablehand-operated vacuum pump is marketed under the trademark MITY VAC II®by Neward Enterprises, Inc. of Cucamonga, Calif.

[0080] The fifth embodiment also includes the seal means 84 whichpreferably consists of a non-foamed, nonporous polyurethane suspensionsleeve 86 for rolling over and covering a portion of the residual limb14. A portion of the seal means 86 is adapted to be disposed between theouter socket 52 and the inner socket 60. The sleeve may be made of anyof a variety of air-impervious elastomers.

[0081] The fifth embodiment, shown in FIG. 10 also includes a mechanicalinterlock 67, 59 for interlocking the inner socket 62 with the outersocket 52. Preferably, the mechanical interlock consists of a firstdetent 67 in the inner socket 62 and a second detent 59 in the outersocket 52. The first detent 67 engages the second detent 59 to lock theinner socket 60 into the outer socket 52.

[0082] A sixth embodiment of the hypobarically-controlled artificiallimb of the present invention is shown in FIGS. 11 and 12. The sixthembodiment is like the first embodiment shown in FIG. 4, with somechanges.

[0083] First, the inner socket is specifically intended to be removablyfrom the outer socket. To provide a positive mechanical connectionbetween the inner socket and outer socket and yet allow the inner socketto be easily removed, the sixth embodiment includes a mechanicalinterlock 103 engaging the inner socket 60 and the outer socket 52.Preferably, the mechanical interlock may be an extension 104 which isattached to the inner socket 60 and a docking device 106 attached to theouter socket 52 and receiving the extension 104, and a locking mechanism105 engaging the extension 104 and the docking device 106.

[0084] The extension may be any sort of protrusion from the innersocket, such as a bulge or tab. Preferably, the extension 104 comprisesa shuttle pin 108.

[0085] The locking mechanism may be any sort of member which engagesboth the extension 104 and the docking device 106, such as a screw,wire, or pin. Preferably, the locking mechanism 105 comprises a secondpin 110 which extends outside the outer socket 52 as to be accessible.

[0086] Second, the sixth embodiment includes two thin sheaths, ratherthan one. A first inner sheath 90 may preferably be disposed between theresidual limb 14 and the inner surface 64 of the inner socket 60. Asvacuum is applied to the cavity 62, the inner sheath 90 will allow thevacuum to be evenly applied throughout the cavity 62. Without the innersheath 90, the residual limb 14 might “tack up” against the innersurface 64 and form a seal which might prevent even application of thevacuum to the cavity 62. The inner sheath 90 may also be used to assistthe amputee into a smooth and easy fitting into the inner socket 60.

[0087] An outer sheath 93 is preferably disposed between the suspensionsleeve 86 and the inner socket 60, thereby preventing the suspensionsleeve from tacking to the inner socket 60. Such tacking would causefriction between the inner socket 60 and the sleeve 86 which would causethe sleeve to wear out. Such tacking might also cause restrictions inthe movement of the residual limb. The outer sheath 93 also protects thesuspension sleeve 86 from being damaged by friction with the innersocket 60.

[0088] The sixth embodiment also preferably includes an adhesivepressure tape 95 adapted to cover the outer sheath 93, suspension sleeve86, and the second sleeve 94 and sealing the outer sheath 93, suspensionsleeve 86, and the second sleeve 94 to the inner socket 60. The tape 95locks all of these layers to the inner socket so that they do not comeloose during movement.

[0089] In the sixth embodiment, the suspension sleeve 86 goes betweenthe inner socket 60 and the outer socket 52, so that the sleeve 86 isprotected from damage.

[0090] In the sixth embodiment, the inner socket 60 has a rigid lowerportion 98 and a substantially flexible upper portion 96. The rigidlower portion assists in weight-bearing while the substantially flexibleupper portion allows for movement of the residual limb 14. As the kneeis bent from fully straight to fully flexed, the width of the kneechanges rather significantly and in a hard, non-flexible socket brim,there can be excessive pressure on the residual limb 14. Thesubstantially flexible upper portion 96 makes the artificial limb 50more comfortable and more adaptive to these changes. For the samereason, the outer socket 52 has a rigid lower portion 102 and asubstantially flexible upper portion 100.

[0091] Preferably, the top edge of the inner socket 60 is below the topedge of the outer socket 52 so that the sleeve 86 is protected fromimpact. Preferably, the top edge of the inner socket 60 may be {fraction(3/16)} inch below the top edge of the outer socket 52.

[0092] The sixth embodiment includes extensive modifications to thevacuum system.

[0093] First, a vacuum fitting 78 has been added to the inner socket 60to attach the vacuum tube 76. The vacuum fitting 78 allows theattachment of a vacuum sensor 79 adapted to sense the amount of vacuumin the cavity 62 and a sensor lead 81 is attached to the sensor 79connecting the sensor 79 to the regulator means 80, thus conveying thesensed vacuum to the regulator means 80.

[0094] A vacuum valve 74 is placed between the cavity 62 and the vacuumsource 70 to maintain vacuum in the cavity 62. Typically, the vacuumvalve 74 is a one-way valve or non-return valve.

[0095] In the sixth embodiment, the vacuum source 70, vacuum tube 76,vacuum valve 74, regulator means 80, and power source 83 are allattached to the outer socket 52 in the space 58 between the outer socket52 and inner socket 60. In this way, these delicate components areprotected against being damaged by impact. Because of the placement ofthe regulator means 80 within the outer socket 52, a vacuum control 77is provided extending outside the outer socket 52 to allow manualcontrol of the regulator means 80.

[0096] The amputee dons the sixth embodiment in a manner similar to thatearlier described, with some modifications. First, the outer sheath 93is put on the residual limb 14 after rolling the suspension sleeve 86upward over the residual limb and before donning the liner 92. Afterdonning the inner sheath 90 over the liner 92, the amputee inserts theresidual limb 14 into the inner socket 60. Next, the outer sheath 93,suspension sleeve 86, and second sleeve 94 are rolled down over theinner socket 60, and the adhesive pressure tape 95 is applied. Next, thewearer sets the regulator means 80 to an appropriate vacuum level bymeans of the vacuum control 77, and connects the vacuum tube 76 to thevacuum fitting 78. The inner socket 60 is then placed within the outersocket 52 so that the shuttle pin 108 engages the docking device 106 andthe locking pin 110 is set to engage the shuttle pin 108 and the dockingdevice 106, providing a positive mechanical interlock.

[0097] A seventh embodiment of the hypobarically-controlled artificiallimb of the present invention is shown in FIG. 13. The seventhembodiment is similar to the sixth embodiment, with some changes.

[0098] First, the mechanical interlock 103 does not engage the innersocket 60. Instead, the mechanical interlock engages the outer socket 52and the suspension sleeve 86. To accomplish this, the suspension sleeve86 covers the entire inner socket 60, and the suspension sleeve 86 hasthe extension 104 or shuttle pin 108 embedded in the suspension sleeveat the distal end of the suspension sleeve, as shown in FIG. 14.Preferably, the extension 104 has a portion 104A embedded in thesuspension sleeve. This portion 104A may be a disk or umbrella 104A. Theextension 104 then engages the docking device 106 as previouslydescribed.

[0099] Second, the suspension sleeve 86 is modified to support theadditional weight imposed on the suspension sleeve 86 due to the outersocket 52 and artificial limb. In particular, the suspension sleeve 86is fabricated from a material which allows circumferential expansion butresists longitudinal stretching under the weight of the artificial limb.Such a material is described in U.S. Pat. No. 5,571,208, hereinincorporated by reference.

[0100] The sleeve 86 preferably contains fabric threads which may beoriented circumferentially around the sleeve. The threads preferably arecomprised of double-knit polyurethane. The threads may also includenylon. The threads permit the sleeve 86 to expand circumferentially sothat the sleeve may be slipped onto the residual limb 14 and so that thelower portion may be slipped over the inner socket 52. The threads arepreferably connected together with cross-links, which also may bepreferably comprised of polyurethane. The cross-links and threads form amatrix which allows circumferential expansion but resists longitudinalstretching under the weight of the artificial limb. By example, thesleeve 86 may have a 4-to-1 ratio of circumferential stretch relative tolongitudinal stretch.

[0101] The sleeve 86 may have a portion above the inner socket 52 whichis manufactured of material which allows both vertical and horizontalstretching, to increase flexibility.

[0102] An eighth embodiment of the hypobarically-controlled artificiallimb of the present invention is shown in FIG. 15.

[0103] Unlike earlier embodiments, the artificial limb 50 of the eighthembodiment has only a single socket 60 rather than inner and outersockets and is thus considerably simpler.

[0104] The socket 60 has a volume and shape to receive a substantialportion of the residual limb 14 with a cavity 62 therebetween.

[0105] A nonfoamed, nonporous polyurethane liner 92 is preferablyadapted to receive the residual limb 14 and to be disposed between theresidual limb 14 and the socket 60.

[0106] A vacuum source 70 is connected to the cavity 62 by a vacuumvalve 78, thereby drawing the residual limb 14 into firm contact withthe socket 60.

[0107] A seal means 84 makes a seal between the residual limb 14 and thesocket 60 to minimize air leakage into the cavity 62. It has been foundthat it is impossible to make a perfect seal, with the result that airleakage can occur at rates up to 30 cc per minute. As air leaks into thecavity 62, it is necessary to activate the vacuum source 70 to restorevacuum in the cavity. Furthermore, it has been found that when thevacuum in the cavity is about 5 inches of mercury, the residual limb maylose up to 6 to 15% of its volume during the day, whereas if the vacuumin the cavity is 15-25 inches of mercury, the residual limb loses onlyabout 1% of its volume during the day.

[0108] To minimize the time that the vacuum source, such as a vacuumpump 72, needs to run to maintain vacuum in the cavity, a ninthembodiment of the artificial limb 50 is shown in FIG. 16. The ninthembodiment is the same as the eighth embodiment, but a vacuum reservoir110 is added between the vacuum source 70 and the vacuum valve 78. Thevacuum reservoir 110 has a volume substantially larger than the cavity62. Suitably, the vacuum reservoir may have a volume of 2 gallons or9000 cc while the volume of the cavity 62 may be only about 100 cc oreven less.

[0109] It will be seen that as air leaks into the cavity 62, the airwill be pulled into the vacuum reservoir 110, thereby maintaining thevacuum in the cavity 62.

[0110] When the vacuum in the reservoir 110 reaches a certain minimumthreshold, the vacuum source 70 may be activated to restore vacuum tothe vacuum reservoir 110. The vacuum source 70 may be activated eithermanually or by a regulator means (not shown).

[0111] The artificial limb 50 typically includes a shin or pylon 54 anda foot 56, as shown in FIG. 3. Preferably, the vacuum reservoir 110 isattached to the shin 54 between the socket 60 and the foot 56. However,the vacuum reservoir may also be carried separately, as for example in abackpack. Depending on the placement of the vacuum reservoir 110, avacuum tube 76 maybe necessary to connect the vacuum reservoir 110 tothe vacuum valve 78.

[0112] If the volume of the vacuum reservoir 110 is about 9000 cc andair leaks into the cavity 62 at about 75 cc per minute, it will be seenthat the intervals between activation of the vacuum source 70 can be upto about 120 minutes.

[0113] The artificial limb 50 of the eighth and ninth embodiments maypreferably further comprise the following.

[0114] An inner sheath 90 may be adapted to be disposed between theliner 92 and the socket, to ensure even distribution of vacuum in thecavity 62, as earlier described. Preferably, the inner sheath 90 may bethin knitted nylon. The sheath 90 may also be affixed to the outside ofthe liner 92.

[0115] The seal means 84 is preferably a nonfoamed, nonporouspolyurethane suspension sleeve 86 for rolling over and covering thesocket 60 and a portion of the artificial limb 14, as earlier described.Seal means may also be an external annular abutting flange or ring 140shown in FIG. 17. Again, seal means may also be an internal annularabutting flange or ring 140 shown in FIG. 18.

[0116] A stretchable nylon second sleeve 94 (see FIG. 3) for rollingover and covering the suspension sleeve 86 may be added to preventclothing from sticking to and catching on the suspension sleeve 86, asearlier described.

[0117] The vacuum source 70 is preferably a motor or mechanical drivenvacuum pump 72, as earlier described. A vacuum tube 76 may be necessaryto connect the vacuum pump 72 to the vacuum valve 78, depending on theplacement of the vacuum pump 72.

[0118] Applicant has found that many of the embodiments discussedearlier share a common problem. The vacuum which holds the residual limb(and liner) in firm contact with the socket tends to cause edema andblistering at the point on the residual limb where the suspension sleevecontacts the residual limb. This problem occurs because the vacuum(perhaps 7½ pounds of negative pressure) in cavity 62 draws against thesuspension sleeve 86 at the point where the suspension sleeve 86contacts the skin of the residual limb. However, because the liner 92often has an outer fabric cover 130 to prevent the liner from adheringto the socket 60 or clothing, the suspension sleeve cannot make a goodseal at the point where it contacts the outer fabric cover 120. This hasleft the residual limb as the only point at which to make the seal.

[0119]FIG. 17 shows one solution to this problem. The liner 92 isimproved by adding an annular seal 140 extending outwardly from thefabric cover 130. The annular seal, which may be made from the samematerial as the inner layer 92 of the liner, is adapted to sealinglyengage the suspension sleeve 86, producing a seal against the vacuum incavity 62 at the point of contact with the suspension sleeve 86.Therefore, the vacuum in cavity 62 now draws against the annular seal130 rather than against the skin of the residual limb 14.

[0120] An alternative solution to the above problem is shown in FIG. 18.Here, the annular seal 140 does not make contact with the suspensionsleeve 86, but rather makes contact with the inner wall 63 of the socket60, and makes a seal at that point. No suspension sleeve is used in thisvariation, it being found that sufficient holding force is provided bythe vacuum in cavity 62. FIG. 18 also shows that the annular seal 140may simply be an extension of the liner 92, passing through the fabriccover 130.

[0121] A second alternative is shown in FIG. 19. This alternative islike that of FIG. 18, with the exception that a mechanical interlock 103is provided which is adapted to interlock with the socket 60.Preferably, as shown, the mechanical interlock 103 comprises a shuttlepin 108 adapted to connect the liner 92 with the socket 60, and alocking mechanism 105 such as a second pin 110 extending through thesocket 60 to the exterior of the socket 60 for access by the amputee asearlier described. More particularly, the liner 92 may have an extension104 or shuttle pin 108 embedded in the liner at the distal end of theliner. Preferably, the extension 104 has a portion 104A which may be adisk or umbrella which engages a docking device 106 as earlierdescribed.

[0122] To keep air from entering the cavity 62, the invention of FIG. 19also preferably includes a locking mechanism seal 150 adapted to engagethe inner wall 63 of the socket 60 about the locking mechanism 105. Theseal 150 could alternatively be on the outer surface of the socket 60.

[0123] Another alternative is shown in FIG. 20. Here, the fabric cover130 stops below the annular seal 140. The annular seal 140 may also bemade of the same material as the liner 92.

[0124] Applicant has found that, by bonding the liner 92 directly to theinside surface 63 of the socket 60, a seal may be produced thatmaintains the vacuum in the cavity 62 without the need for a separateannular seal or vacuum seal. FIG. 21 shows this embodiment.

[0125] In FIG. 21, the liner 92 is bonded directly to the inside surface63 of the socket 60 by an adhering interface 64.

[0126] The adhering interface 64 may be such as to provide a permanentattachment of the liner 92 to the socket 60, or a semi-permanentattachment that allows the liner 92 to be removed and replaced.

[0127] The adhering interface 64 may be any interface that has twoadhering surfaces. One adhering surface 64 a preferably adheres to theliner 92 while the other adhering surface 64 b preferably adheres to theinside surface 63 of the socket 60.

[0128] Possible embodiments of a permanent attachment for the adheringinterface 64 are: a laminating adhesive, i.e., a thin film placed on thesurface of the liner and the liner 92 then being inserted into thesocket 60; contact cement; or any type of paint-on glue.

[0129] Possible embodiments of a semi-permanent attachment for theadhering interface 64 are: a hook and loop fastener fabric such asVelcro®; or cooperating magnets in both the liner 92 and the socket 60.

[0130] To don the artificial limb, the wearer inserts the residual limbinto the liner, which is already attached to the socket by the adheringinterface.

[0131] Additional connections may be employed between the residual limband the socket, such as the nonfoamed, nonporous polyurethane suspensionsleeve earlier described and the mechanical interlock also previouslydescribed.

[0132] The present invention may be embodied in other specific formswithout departing from the spirit or essential attributes thereof, andit is therefore desired that the present embodiment be considered in allrespects as illustrative and not restrictive, reference being made tothe appended claims rather than to the foregoing description to indicatethe scope of the invention.

What is claimed:
 1. An artificial limb for an amputee, the artificiallimb comprising a liner configured to receive a portion of an amputee'sresidual limb, a socket configured to removably receive the liner andthe residual limb, and a liner interface for removably bonding the linerand the socket.
 2. The artificial limb of claim 1, wherein the linerinterface is configured to substantially seal the liner to the socket tominimize air leakage into space between the liner and socket.
 3. Theartificial limb of claim 1, wherein the liner interface comprises atleast one adhering surface that bonds to one of the liner and socket. 4.The artificial limb of claim 1, wherein the liner interface comprisestwo adhering surfaces, a first surface that bonds to the liner and asecond surface that bonds to the socket.
 5. The artificial limb of claim4, wherein the liner interface comprises a double sided adhesive layer.6. The artificial limb of claim 1, wherein the liner interface compriseshook and loop material.
 7. The artificial limb of claim 1, wherein theliner interface comprises magnetic material, such that magnetic materialon the socket is attractable to magnetic material of the liner.
 8. Aliner for a socket of an artificial limb configured to received anamputee's residual limb, the liner comprising a liner interface forremovably bonding the liner and the socket.
 9. The liner of claim 8,wherein the liner interface is configured to substantially seal theliner to the socket to minimize air leakage into space between the linerand socket.
 10. The liner of claim 8, wherein the liner interfacecomprises at least one adhering surface that bonds to one of the linerand socket.
 11. The liner of claim 8, wherein the liner interfacecomprises two adhering surfaces, a first surface that bonds to the linerand a second surface that bonds to the socket.
 12. The liner of claim11, wherein the liner interface comprises a double sided adhesive layer.13. The liner of claim 8, wherein the liner interface comprises hook andloop material.
 14. The liner of claim 8, wherein the liner interfacecomprises magnetic material, such that magnetic material on the socketis attractable to magnetic material of the liner.
 15. An artificial limbfor an amputee, the artificial limb comprising a socket configured toremovably receive a residual limb of an amputee, the residual limbreceived within a liner, and a liner interface for removably bonding theliner and the socket.
 16. The artificial limb of claim 15, wherein theliner interface is configured to substantially seal the liner to thesocket to minimize air leakage into space between the liner and socket.17. The artificial limb of claim 15, wherein the liner interfacecomprises at least one adhering surface that bonds to one of the linerand socket.
 18. The artificial limb of claim 15, wherein the linerinterface comprises two adhering surfaces, a first surface that bonds tothe liner and a second surface that bonds to the socket.
 19. Theartificial limb of claim 18, wherein the liner interface comprises adouble sided adhesive layer.
 20. The artificial limb of claim 15,wherein the liner interface comprises hook and loop material.
 21. Theartificial limb of claim 15, wherein the liner interface comprisesmagnetic material, such that magnetic material on the socket isattractable to magnetic material of the liner.
 22. A method of removablyattaching an artificial limb to a residual limb of an amputee, theartificial limb including a socket configured to removably receive theartificial limb, the method comprising the step of removably bonding thesocket to a liner received about the residual limb.
 23. The method ofclaim 22, further comprising the step of sealing the liner to the socketto minimize air leakage into space between the liner and socket.
 24. Themethod of claim 22, wherein the step of bonding comprises providing aliner interface.
 25. The method of claim 24, wherein the liner interfacecomprises at least one adhering surface that bonds to one of the linerand socket.
 26. The method of claim 24, wherein the liner interfacecomprises two adhering surfaces, a first surface that bonds to the linerand a second surface that bonds to the socket.
 27. The method of claim26, wherein the liner interface comprises a double sided adhesive layer.28. The method of claim 24, wherein the liner interface comprises hookand loop material.
 29. The method of claim 24, wherein the linerinterface comprises magnetic material, such that magnetic material onthe socket is attractable to magnetic material of the liner.
 30. Anartificial limb for an amputee, the artificial limb comprising a meansfor removably receiving a portion of an amputee's residual limb receivedwithin a liner and a means for removably bonding the liner and the meansfor receiving.
 31. The artificial limb of claim 30, wherein the meansfor bonding substantially seals the liner to the means for bonding tominimize air leakage into space therebetween.
 32. The artificial limb ofclaim 30, wherein the means for receiving comprises a socket.
 33. Theartificial limb of claim 30, wherein the means for bonding comprises aliner interface.
 34. The artificial limb of claims 33, wherein the linerinterface comprises at least one adhering surface that bonds to one ofthe liner and socket.
 35. The artificial limb of claim 33, wherein theliner interface comprises two adhering surfaces, a first surface thatbonds to the liner and a second surface that bonds to the socket. 36.The artificial limb of claim 35, wherein the liner interface comprises adouble sided adhesive layer.
 37. The artificial limb of claim 33,wherein the liner interface comprises hook and loop material.
 38. Theartificial limb of claim 33, wherein the liner interface comprisesmagnetic material, such that magnetic material on the socket isattractable to magnetic material of the liner.